OpenAPI change checker

What it does

Compare two OpenAPI 3.1 JSON specifications and flag potentially breaking changes and unsupported cases.

How to use it

1. Paste or import the previous and new specifications, then compare.
2. Review each finding and export the JSON report. Servers, webhooks, serialization and undocumented behaviour are outside scope.
3. Processing stays in your browser. No upload or sign-up.

Example

Compare the preset GET /pets specs to flag the newly required limit parameter.

Methodology

A bounded worker compares operations, parameters, request bodies and response schemas with direction-specific required and enum rules.

Limitations

JSON only; 2 million characters per document, 1,000 combined paths and 2,000 findings. Local references only. A finite rule set cannot prove compatibility; unsupported schemas are marked unknown.

Automation

This tool runs in your browser. No upload API or MCP endpoint is available.